The average height of 50 students in a class is 182 cm. 40 students whose average height is 182.5 cm left the class and 50 students whose average height is 180.5 cm joined the class. Find the average height of the present? A) 180.41 B) 175.5 C) 180.55 D) 185.5

1 Answer

Answer :

A)

The average of the students leaving the class as well as joining the class to be 182 so that the average

remains the same.

But it is given that the average of the 40 students leaving the class is 182.5 (more than 182).

So we will incur a loss of 0.5 cm in the average upon 40 students.

Hence the loss in the sum = 0.5x 40 = 20 cm

Also, since the average of the 50 students joining the class is 180.5 (less than 182) we will incur a loss in this

case as well. The loss in the average is 1.5 cm upon 50 students.

Hence the loss in the sum = 1.5x50 = 75 cm

Thus the total loss in the sum = 95 cm. This loss will be shared by 60 students which is the present strength of

the class.

Hence the average of the present class = 182 – 95/60 = 180.5 cm

Related questions

Description :  The average height of a batch is 344 cm. 16more students with an average height of 320 cm joined the batch therefore decreasing the average height of the batch by 12 cm. Find the total strength of the batch? A) 12 B) 11 C) 14 D) 16 

Last Answer : Answer: D) let the initial strength of the batch be X total height of the batch initially = 344X total height of 16 new students = 320 * 16 = 5120 cm Then, the average height of X+ 16students = 332  332 = [5120 + 344 X]/ [X + 16]  X= 16 students

Description : A group of students of arithmetic mean of the marks in a test was 63. The brightest 30% of them secured a mean score of 70 and the dullest 15% a mean score of 41. The mean score of remaining 55 % is A) 63.675 B) 61.785 C) 65.181 D) 66.67

Last Answer : C) Let the requird mean score be ‘x’ Then (30*70)+(15*41)+55x = 63*100 2100+615+55x=6300 2715+55x=6300 55x=3585 X=65.181

Description : The average height of the students in a group was 360cm. When 10 students whose height is 292.8cm are newly admitted. The average height of the group was reduced by 24cm.How many students are present in the group? A) 29 B) 25 C) 28 D) 14

Last Answer : Answer: C) let the number of students initially in the class be A, then, total height = A * 360------ 1 again the no of students increased = A + 10 then, total height A + 10 student = (A +10) * 336 ... 3 (A+10) *336-2928 =A*360 336A+3360-2928=360A A=18 Number of students in class = 18+10=28

Description : A students maks were wrongly entered as 72 instead of 52. Due to that the average marks for the class got increased by half. The number of students in the class is. A) 50 B) 56 C) 46 D) 40

Last Answer : D)  Let there be y students in the class Total increase in marks = y *1/2 = y/2 Therefore y/2 = (72 – 52) y/2 = 20 y = 40

Description : The Bactrian Greeks arrived in Gandhara in: A. 175 BC B. 182 BC C. 185 BC D. 165 BC

Last Answer : ANSWER: C

Description : The average age of 150 students in a class is 40% of the number of students in the class and the average age of a group of 50 students present in the class is 32yrs and the average age of another 50 students ... is the average age of the remaining students in the class? A) 102 B) 118 C) 112 D) 108

Last Answer : C) 150 students average 150×40/100=60 years According to the question, 150×60=50×32+50×36+50×X 50×X=9000-1600-1800 50x=5600 X=112

Description : The average of 7 consecutive odd numbers is 41. Find the largest of these numbers A) 40 B) 57 C) 47 D) 43

Last Answer : C) Let the numbers be x , x+2,x+4,x+6, x+8, x+10 and x+12 Then x+x+2+x+4+x+6+x+8+x+10+x+12/7 7x+42=287 7x=245 X=35 Largest number = x+12 = 35+12 =47

Description : A cricket player had a certain average of runs for his 43 innings. In his 44th innings, he is bowled out for no score on his part. This brings down his average by 4runs. His new average of runs is ? A) 172 B) 182 C) 166 D) 162

Last Answer : A) Let the cricket player’s average of runs for his 43 innings be X runs. Total number of runs in 43innings=43x According to the question, [43x + 0]/ 44= x-4 43x = 44x – 176 x = 176 new average of runs = 176-4 =>172

Description : When a girl weighing 90 kgs left a class, the average weight of the remaining 119 students increased by 400 g. What is the average weight of the remaining 119 students? A) 124 B) 138 C) 145 D) 116

Last Answer :  B Let the average weight of the 119 students be X. Therefore, the total weight of the 119 of them will be 119X. The questions states that when the weight of this student who left is added, the total ... , the average weight decreases by 0.4 kgs. (119X+90)/120=X−0.4 ⇒119X+90=120X−48  ⇒X=138

Description : The average marks scored by two Class A1 and A2 students are 120 and 130 respectively. If 8 students are moved from Class A2 to Class A1 and the average marks of the two Class get interchanged. Find the total number ... average marks scored by the 8 students who moved is 150 A) 25 B) 30 C) 35 D) 40

Last Answer :  D)  let the number of students in Class A1 be x and class A2 be y. Total marks scored by the students will be 120x and 130y, the average gets interchanged after moving student from y Thus we get, 130y- ... (x+8) 120x+1200=130x+1040 10x=160 X=16 Thus the total number of students =24+16=40

Description : The average score in a bank examination of 13 students of a class is 50. If the scores of the top five students are not considered, the average score of the remaining students falls by 5. The pass mark ... integral scores, the maximum possible score of the topper is. A) 85 B) 90 C) 95 D) 100

Last Answer : D Average = Sum of observations/Number of observations Given, average score in a bank examination of 13 students of a class is 50. Sum of total scores = 13 50= 650 Given, if the scores of the top five students are not ... b + c + d + e = 290 ⇒46+ 47 + 48+ 49 +e = 290 ⇒e = 100

Description : The average weight of M,N and O is 168 kg. If P joins the group, the average weight of the group becomes 160 kg. If another man Q who weighs 6kg more than P replaces M, then the average of N,O,P and Qbecomes158 kg. What is the weight of M? A) 175 B) 140 C) 145 D) 150 

Last Answer : D) M+N+O =168 * 3 =504 M+N+O+P=160*4=640……(1) P=136 kg and Q =142 kg N+O+P+Q =158*4 =632 N+O+P =632-142 =490…..(2) from 1 & 2, M=640-490 =150kg

Description : A certain company employed 600 men and 400 women and the average wage was 2.55 per hour.If a women got 50 paise less than a man, what were their wages per hour ? (a) Man rs 3.00,Woman Rs 2.50 (b) Man Rs 3.50, Woman Rs 3.00 (c) Man Rs 2.75, Woman Rs 2.25 (d) Man Rs 3.25, Woman Rs 2.75

Last Answer : Man = Rs 2.75, woman = Rs 2.25

Description : When the average age of a father, mother and their son was 90 years, the son got married and a child was born just 6 year after the marriage when child turned 14 years the average age of the family is 80yrs. Find the age of daughter - in - law at present? A) 55 B) 56 C) 57 D) 58

Last Answer : B) total age of father, mother and son at the time of son's marriage = 90*3 =270 present age of family father, mother, son, daughter-in-law, child = (father, mother, son age at the time of marriage ... 60)+ daughter-in-law present age + 14 = 80*5 =400 daughter-in-law present age= 400-344 = 56yrs

Description : Students of two university appeared for a common test of maximum 60 marks. The average of their marks for university 1 & university 2 are 39 & 42 respectively. If the no of students of university 1 is twice the no ... the average marks of all students of both the university? A) 40 B) 42 C) 26 D) 36

Last Answer : Answer: A) Let number of students of university2 be N and the no of students of university 1 be 2N the average of university1 and university 2 is 39 and 42 total marks of university 1 students and university 2 ... 78N and N*42 =42N average of both university,  =(78N+42N) /(N+2N) = 40 marks

Description : The average of 3,8,7 and a is 6 and the average of 19,2,7, a and b is 11. What is the value of b? A) 11 B) 21 C) 31 D) 41 

Last Answer : B) We have (3+8+7+a+6/5)=6 24 =a = 30 A=6 Also (19+2+7+a+b/5)=11 19+2+7+6+b=55 34+b=55 b=21

Description : Find the average of first 85 natural numbers? A) 43 B) 41 C) 45 D) 47

Last Answer : A) Sum of 1st n natural numbers = n(n+1)/2 So, sum of 1st 85 natural numbers = 85(85+1)/2 =85(86)/2 =7310/2 =3655 Required average = 3655/85 =43.

Description : The average height of 60 girls was calculated to be 300 cm. It was detected later that one value of 330 cm was wrongly copied as 270 cm for the computation of the mean. Find the correct mean. A) 301cm B) 300.5cm C) 307cm D) 311cm

Last Answer : A) Calculated average height of 60 girls = 300cm. Incorrect sum of the heights of 60 girls = (300 60)cm = 18000 cm. Correct sum of the heights of 60 girls = (incorrect sum) - (wrongly copied item) ... 330) cm = 18060cm. Correct mean = correct sum/number of girls = (18060/60) cm = 301 cm.

Description : The average age of three -seventh of class is 49, what should be the average of remaining four-seventh students so that the average of the entire class is 63? A) 24.5 B) 86.5 C) 73.5 D) 25.5

Last Answer : C) According to the question, 63=3/7×49+4/7×y 63=147/7+4y/7 441=147+4y 4y=294 Y=73.5

Description : The average of marks obtained by 60 students in a computer examination is 18. If the average marks of passed students is 20and that of the failed students is 8, what is the number of students who passed the examination? A) 100 B) 75 C) 50 D) 85 

Last Answer : C Let the number of passed students be x. Then total marks = 60 × 18= 20x + (60– x) × 8 1080= 20x + 480– 8x 12x = 600 ∴ x = 50 ∴ number of passed students = 50

Description : There are three different categories of jobs A, B and C. The average salary of the students who got the job of A and B categories is Rs.32 lakh per annum. The average salary of the student who got the job of B ... 30 & 44 B) lies between 48 & 56 C) lies between 38 & 45 D) lies between 49 & 50

Last Answer : Answer: C) Let the number of students who got the jobs of A, B and C categories is a, b and c respectively, ∴Total salary of Aand B = 32 (a +b) ∴Total salary of B and C = 54 (b+ ... the minimum salary must be Rs.38 lakh and the maximum salary cannot exceed 45, which is the highest of the three..

Description : The average age of students of a college is 31.6 yrs. The average age of boys in the class is 32.8 yrs and that of girls is 30.8. The ratio of number of boys to the number of girls in the class. A) 2:3 B) 3:1 C) 1:3 D) 3:2

Last Answer : A) Let the ratio be D:1.then, (D * 32.8) + ( 1* 30.8)= (D+1) * 31.6 32.8 D +30.8 = 31.6 D + 31.6 32.8 D – 31.6D = 31.6 – 30.8 1.2D = 0.8 D = 0.8/1/2 = 0.4/0.6 D = 2/3 Required ratio = 2/3 :1 = 2:3.

Description :  on analyzing the result of an competitive exam the teacher found that the average for the entire the class was 69 marks. If we say that average of 10 % of the students scored 77 marks and average of 28 % of the ... marks of the remaining students of the class A) 67.54 B) 68.26 C) 66.91 D) 69.06 

Last Answer : D) average of entire class = 69marks average of 28 % of the students = 66 marks average of 10% of the students = 77 marks then % of remaining students = (100- 10 - 28) = 62% let the average of 62% of the ... (62*x)+770+1848= 6900 62 * x = 6900-770-1848 62*x = 4282 x = 69.06

Description : The average marks of a class of 90 students is 126. Out Of them, 4 scores zero, first 60 students scored an average of 116, next 24 scored an average of 118. What is the mark obtained by the remaining student in the class? A) 750 B) 862 C) 774 D) 875

Last Answer : C) According to the question, 90*126=(4*0)+(60*116)+(24*118)+2y 11340=6960+2832+2y 2y=1548 y=774

Description : There are two groups of a class consisting of 72 and 88 students respectively. If the average weight of 1st group is 80kg and the weight of 2nd group is 70kg. Find the average weight of whole class? A) 64kg B) 74.5kg C) 84.5kg D) 54kg

Last Answer :  B)  Total weight of (72 + 88) = (72*80) + (88 * 70)kg = (5760 + 6160)kg  = 11,920kg  Average weight of the whole class = 11920 / 160  = 74.5 kg

Description : The average salary per head of all the employees in a company is Rs. 180. The average salary of 24 employees is Rs. 1040and the average salary per head of the rest is Rs. 160. Find the total number of employees in the workshop. A) 2841 B) 1056 C) 1195 D) 2145

Last Answer :  B) Average = Sum of observations/Number of observations Let the number of employees be x. Given, the average salary per head of all the employees in a company is Rs. 180 So, the sum of salary of all the employees in ... (x - 24) = 180x ⇒ 24960+ 160x - 3840 = 180x ⇒ 20x = 2112 ⇒ x = 1056

Description : The average age of 14 mens is increased by 1 year when one of them whose age is 44 years is replaced by a lady. What is the age of the lady? A) 54 B) 58 C) 50 D) 56 

Last Answer : B) suppose the average age of 14 men is x years and the age of lady is y years. the total age of 14 mens will be = 14x years the average age of 14 mens is increased by 1 years who of them whose age is 44 years is replaced by ... 14x - 44 + y = 14* (x+1) 14x - 44 + y = 14x + 14 y = 14+ 44 y=58

Description : An industry employed 1200 men and 800 women and the average salary was Rs 51 per day. If a woman got Rs 10 less than a man , then what are their daily salary?(mens and women respectively) A) men Rs 25 and women Rs ... Rs 45 and women Rs 55 C) men Rs 35 and women Rs 25 D) men Rs 55 and women Rs 45

Last Answer : D) Let the daily salary of man be Rs’x’ Then the daily salary of a women = Rs (x-100 Now 1200x + 800(x-10) = 51 *(1200+800) 1200x+800x -8000 = 51*2000 2000x = 102000+8000 =110000 X=55 Therefore mens daily salary Rs 55 and womens daily salary Rs 45

Description : The average age of 160 boys in a class is 58 yrs. The average group of 30 boys in the class is 42 yrs and the average of another group of 50 boys in the class is 36 years. What is the average age of the remaining boys? A) 72.58 B) 74.25 C) 77.75 D) 75.68 

Last Answer : C) Total age of 160 boys = 160* 58= 9280 total age of 30 boys = 30 * 42= 1260 total age of next 50boys = 50 * 36= 1800 average of the remaining boys = [(9280-{1260+1800})/[160 - (30 + 50)] =>9280-3060/80 =>6220/80 =77.75yrs

Description : The average age of 78 students of a batch is 30 years. If the age of the head master be included, then the average increases by 6 months. Find the age of head master? A) 56yrs 5 months B) 66yrs 6 months C) 56yrs 5 months D) 69yrs 5 months

Last Answer : D)  Total age of 78 students = (780 * 30)yrs  = 2340 yrs  Average of 79 persons = 30 yrs 6 months  = 6 ½ yrs  Total age of 79 persons = 61/2 * 79  = 2409.5  Age of headmaster = (2409.5 – 2340)yrs  = 69.5 yrs = 69 yrs 5 months.

Description : Students of two colleges appeared for Talent test carrying 250marks as maximum. The average of their marks for college1 & college 2 are 160 & 180respectively. If the number of students of college 1 is the half of the ... marks of all students of both the college? A) 170 B) 110 C) 173.33 D) 177.33

Last Answer : C) let the number of students of college 2 be '2N' then the number of students of college1 is 'N' the average marks for college1 is 160 the average marks for college 2 is 180 total marks of ... = 360N average marks of all students of both the colleges = (160N + 360N)/N+2N = 173.33marks

Description : The average scores of a batch of students in a test is 84. The 36% of students's average score is 57 and 42% of students's score is 84. Then find the average score of remaining 22% of students approximately, A) 128 B) 131 C) 119 D) 106 

Last Answer : Answer: A)  let the number of students be 100, then, 100*84 = 36*57 + 42*84 + 22*x 22x = 8400-2052-3528 x = 128.18

Description : 1/2of a certain travel is covered at the rate of 30km/hr, one-third at the rate of 40 km/hr and the rest at 35km/hr. Find the average speed for the whole travel. A) 33 1/3 B) 33 3/5 C) 34 3/7 D) None of these

Last Answer : B) let the total travel be X km.  Then X/2 km at the speed of 30 km/hr and X/3 km at 40 km/hr and the rest distance( X - X/2 - X/3) =1/6 X at the speed of 35km/hr. Total time taken during the travel ... 2*30 hrs+ X/3*40hrs+ X/6*35hrs = 5X/168 hrs Average speed =X/(5x/168) = 168/5 =33 3/5km hr

Description : What is the height of 60 kg rail section? a. 180 mm b. 172 mm* c. 185 mm d. 165 mm

Last Answer : b. 172 mm*

Description : The average age of a board of 8 trustless remains the same as it was 3 years ago, when one of them is replaced by a new member. The new member is younger than the truetee in whose place he has been replaced by (a) 24 years (b) 26 years (C) 47 years (d) 32 years

Last Answer : 24 years 

Description : Average age of A, B, C is 90yrs, however when D joins them, then the average comes down to 80 yrs. Now a new person E, whose age is six-fifth of the age of D, replaces A and the new average is 78. What is age of A? A) 64 B) 68 C) 62 D) 66

Last Answer : B) according to the question A+B+C/3=90 => A+B+C =270…………..(1) A+B+C +D/4=80 => A+B+C +D=320………(2) From the equation 1 and 2 D=50 E =6/5×50=60 E+B+C +D/4=78 => E+B+C +D =312 B+C +D =312-60=252……………..(3) From 2and 3 The age of A=320-252=68

Description : In an examination mahi scores 64% of marks, nitesh scores 52% of marks and ritesh scores 48% of marks. The maximum mark of the exam is a three digit number, whose sum is 10 and the middle digit is equal to ... what is the average mark obtained by mahi, nitesh and ritesh? A) 247 B) 248 C) 264 D) 284

Last Answer : A) Maximum mark consist of a three digit number let's consider Unit digit place is Z,ten's place digit is Y and hundred's place digit is X. According to the question, Y=x+z---------1 X+Y ... Total number of Mahi, Nitesh and Ritesh =164/100 451=739.61 Required average =739.64/3=246.54~247.

Description : The average monthly salary of 24 labours and 6 supervisor in a factory was Rs. 1200. When one of the supervisor whose salary was Rs. 1440, was replaced with a new supervisor, then the average salary of the team went down to 1160. What is the salary of the new supervisor? A) 170 B) 420 C) 390 D) 240

Last Answer : D) The total salary amount = 30 1200=36000 The salary of the exiting supervisor = 1440 Therefore, the salary of 24 labours and the remaining 5 supervisors: =36000-1440=34560 When a new ... 34800=1200 less than that of the old supervisor who left the company, which is equal to 1440−1200=240

Description : The average weather(rainfall) for the first 6 days out of 8 days recorded to be 9 cm. The rainfall on last 2 days was in the ratio 2:3. the average of 8 days was 14.2 cm. What was the rainfall on the last day? A) 7.8 B) 34.4 C) 35.76 D) 8.9

Last Answer : C) according to question (6×9+3x+2x)/8=14.2 54+5x=113.6 X=11.92 Last day rainfall=3×11.92=35.76cm

Description : The Cricketer average score in 40 over is 21, if the man scores 23runs in 8over, 26 runs in 10 over and 18runs in 14 over. What is the average score in remaining over? A) 18 B) 19 C) 16 D) 20 

Last Answer : A) According to the question 40*21=23*8+26*10+18*14+8×X 840=184+260+252+8x 8x=144  X=144/8=18 runs

Description : If the average of two numbers are 138& product is 2241. Then find the difference of both numbers? A) 225.40 B) 259.25 C) 267.81 D) 294.57

Last Answer : B) let the two number be a & b sum of two numbers, a+b = 138*2 =276---1 product of two numbers, a*b=2241 (a+b)2 = a2 + 2ab + b2 ------2 (a-b)2 = a2 -2ab +b2 ------3 solving 2 & 3, 76176 - (a-b)2 = 4*2241 a-b = 259.25

Description :  The average age of K and L is 48 years. If M replaced K, the average age would be 40 and if M replaced L, the average would be 44. What are the ages of K,L,M repectively? A) 58, 46, 22 B) 32, 44, 36 C) 52,44,36 D) 56, 22,38

Last Answer : Answer: C)  Total age of K& L = 48*2 = 96 yrs----->1 Total age of L& M = 40*2 = 80yrs----->2 Total age of K& M = 44*2 = 88 yrs----->3 from 1, 2, 3 K+L+M =132---->4 from 1 & 4, M= 36 from 2 & 4, K=52 from 3 & 4, L=44 Hence the required answer is 52,44,36 

Description : The average weight of 45 passenger on board an aircraft is 50 kg. If the weight of 5 members of the crew is added, the average is reduced by half kilogram . What is the average weight of the crew members?

Last Answer : Total weight of 45 passenger = 45 x 50 = 2250 kg Total weight of 45 passenger and 5 crews = 50 x 49.5 = 2475 kg Total weight of 5 crews = 2475-2250 = 225kg Average weight of 5 crews = 225/5 = 45kg.

Description : The average monthly expenditure of Mr. Abi family for the first 4 months is Rs.4210, next 4 month expenditure Rs.4450 for the last 4 months Rs. 4360 . If his family saves Rs. 6800 for 12 months, find the average monthly ... the 12 months? A) Rs. 4707.25 B) Rs.4564.75 C) Rs. 4906.66 D) Rs. 4806.50

Last Answer : C) Mr Abi family first 4 month expenditure=4210*4=16840 Mr Abi family next 4 month expenditure=4450*4=Rs17800 Mr Abi family last 4 month expenditure=4360*4=Rs.17440 Mr Abi family total ... 17440+6800=Rs.58880. Mr Abi family average expenditure in 12 months =58880/12=Rs.4906.66

Description : The average marks obtained by a student in Tamil, english, maths, science, and social together is 65% above the average mark obtained in maths and science together. How many more marks exceeded by the average of ... of the tamil and english together? A) 50 B) 65 C) Data insufficient D) None of these

Last Answer : C) According to the question  There is no other information about the marks in any one of the subject. The data gives is insufficient to answer the question.

Description :  There are 50 compartments in a Chennai express carrying an average of 70 passengers per compartments. At least 24 passengers were sitting in each compartment, not any compartment has equal number of passengers, ... can be accommodated in 50th compartment? A. 748 B. 705 C.739 D.cannot be determined 

Last Answer : C) Total number of passengers in Chennai express = 50*70 = 3500 Total number of candidates from 1 to 49 compartments = 24+25+....+70 = (70*71)/2 +(23*24)/2 = 2761 number of passengers in 50th compartment = 3500 - 2761= 739

Description : A batch of 50 people has the oldest person with 160 years of age. The average of the batch is reduced by 2, if the oldest person is replaced by someone new, Find the age of the new person. A) 45 B) 30 C) 60 D) 75

Last Answer : Answer: C)  Average=Sum of observations/Number of observations Given, a batch of 50 people has the oldest person with 160 years of age. Let the average of the group be a'. Sum total of ages = 50 a Given, average of the ... person be b' . 50a - 160 + b = 50(a - 2) b= 160-100 b = 60 years

Description : The average age of a morning class is 108, if the average age of 72 ladies in the class is as same as the total average and the number of gents in the class is 2 more than the ladies in the class, what is the average age of gents in the class? A) 152 B) 108 C) 156 D) 154 

Last Answer : B) According to question, (72+74)X=72×108+74X 146x-74x=7776 72x=7776 X=7776/72= 108years

Description : 20 years ago, the average age of a family of 4 member was 48 years. 2 children having been born (with the age difference of4 yrs) the present average age of the family is the same. The present age of the youngest child is. A) 2yrs B) 4 yrs C) 6yrs D) 8yrs

Last Answer : C) Total age of 4 members, 20 yrs ago = (48 * 4)=192 yrs Total age of 4 members now = 192 + 20 * 4 = 272 yrs Total age of 6 members now = (48*6)=288yrs Sum of the age of children = 288 - 272 = 16 ... the age of the elder child 4 +x So x + 4 +x = 16 2x=12 X=6 Age of younger child = 6years

Description : The average age of Anu, banu and tonu is 74 yrs. 10years hence the average age of anu and tonu is 86 yrs.6yrs ago the average age of aarthi and banu was 72 yrs. Find the present age of aarthi. A) 80 B) 86 C) 84 D) 83

Last Answer : B) anu+ banu+ tonu = 74 * 3 = 222yrs 10yrs hence, anu + 10 + tonu +10 = 86 * 2 anu + tonu= 152 banu = 222-152 = 70 yrs aarthi -6 + banu - 6= 72 * 2 aarthi + banu = 144 + 12 = 156 aarthi age = 156-70 aarthi age = 86yrs